This invention relates to a finger splint for fixing the distal finger joint in the extended position, consisting of a shell supporting the distal finger joint and the distal phalanx on the underside, and a shell supporting the distal finger joint and the middle phalanx on the upper side, which shells are connected to one another near the distal finger joint by means of an annular part.
In known finger splints of this type (EP-A 0,183,021), the two shells are in each case made undivided. Therefore, even if they are made of deformable material, they are nevertheless practically unable to yield. This has the disadvantage that the splint cannot resiliently follow, for example, subsiding swellings at the base of the distal phalanx of the finger. In the usual applications of finger splints, for example fractures of the distal phalanx, surgical care of extensor tendon ruptures and inflammation of the nail area, the distal phalanx of the finger is significantly swollen and sensitive, particularly on the dorsal side. This makes it necessary to use correspondingly larger splints which, however, then prove too wide in the area of the middle phalanx of the finger and therefore fit poorly and cannot be fixed correctly. They twist round easily and do not give correct support.
In U.S. Pat. No. 2,528,456 an attempt is made to provide a finger splint with the possibility of adapting to different finger diameters in the different areas of its longitudinal extent by virtue of the fact that it is composed of a plurality of tongues which extend in the circumferential direction and are secured on a common, continuous splint part. The tongues are made elastically resilient so that they can adapt to the thickness of the particular area of the finger surrounded by them, and their ends overlap the continuous splint part. The resilient tongues have the disadvantage that they continuously and unavoidably exert pressure on the finger. This is exactly what it is intended to avoid using the type of finger splint to which the invention relates, namely by using two shells lying on opposite sides of the finger, in different areas thereof, adapted to the shape of the finger and connected rigidly to one another.
EP-A 0,162,692 discloses a finger splint which comprises a resilient annular part, and departing from this and extending in the longitudinal direction, tongues which are held together by means of displaceable rings. Depending on the thickness of the finger, narrower or wider rings can be pushed on, by means of which the tongues extending in the longitudinal direction are held together more tightly or more loosely. In this case, the set spacing of the longitudinal tongues in each case corresponds to the thickest part of the finger, whereas it cannot lie on the thinner areas. The consequence of this is that no correct guiding can be obtained in the thinner areas of the finger.
DE-A 3,026,839 discloses a finger splint of the type to which the invention also relates. It is connected by means of a link to a further splint part which is supported on the proximal phalanx of the finger and is slotted. In contrast, those splint parts supporting the distal phalanx on the underside and the middle phalanx on the upper side are made rigid and undivided in the conventional manner. This document is therefore evidence of the previous medical view that the generic type of finger splint must be rigid per se in order to be able to achieve the desired, anatomically adapted support effect.